Marine markers are an important tool for the maintenance of commerce on navigable waterways. Their use is, among others, to identify navigable waterways that boat and ship operators might follow the safe water route in and out of a harbor or up and down an inland river. Pleasure craft rely upon marine markers to avoid hazardous areas in recreational waterways and safely operate in transit in coastal areas and inland rivers and lakes. Regulatory agencies including the U.S. Corps of engineers, Coast Guard, state and federal parks departments, sheriffs departments, harbor authorities and private entities including yacht clubs and resort enterprises utilize marine markers to establish safety and operating rules for use of these waterways.
Once placed, the marine marker is then continually relied upon to provide its informational role, irrespective of weather conditions. The marker is exposed to the vagaries of climate, storm, sun and the pounding of the physical environment in which it survives. The continuing exposure of the marker to the ultraviolet rays of sunlight is known to cause degradation of commonly used plastics. The continued bathing of the fresh and salt water environment either wears on the surface finish on the marker (including the illustrative/informative message printed, painted or otherwise embodied thereon) or physically or chemically attacks the material of which the marker is constructed. While plastics materials provide relatively more chemical stability, the physical effects of the marker environment may have dictated the use of a metal or alloy thereof to provide effective longevity. Though the continued bombardment of the likes of waves, wash, rain, wind that marine markers endure are substantial, they are continually assaulted by the vessels traversing the waterways. Thus, in addition to surface stability against weather and sunlight, the marker must also have structural rigidity to withstand the battering intermittently imposed.
Where the physical integrity of a marine marker may provide several years of service, the environmental abuse may cause the informational messages to be obliterated or blurred, whereby the marker is non-functional. It is common practice to employ maintenance and restorative programs to ensure the functional operation of marine markers. Included in these functions are the cleaning of the markers to remove marine growth, repair of physical damage, restoration of faded or obliterated symbols, messages and marks or bands and refinishing the surface with a protective coating to prolong surface appearance and stability. Such programs include the application of such as vinyl labels and panels over the surface of the marker to replace the message or marking originally carried and subsequently applying a further protective coating to prolong the functionality.
Markers are conventionally fabricated of elements to be assembled as containers which are then filled with light weight materials such as a urethane foam for additional structural rigidity and buoyancy. Additionally, markers are conventionally provided with a nominal fill of a concrete or other heavy material to provide ballast and orientation to the marker as it floats in its anchored state. Prior art materials utilized for the manufacture of markers include high density polyethylene (HDPE), acrylonitrile-budatiene-styrene (ABS) and metal alloys treated to withstand the corrosive effects of the water environment.
Examples of such prior art marine markers are illustrated in a catalogue of such products available from Smith & Nephew Rolyan Inc., the assignee of the present invention.